Ti3SiC2 MAX-Phase-Based Composites Produced by Vacuum and Spark Plasma Sintering

For the synthesis of composites based on the MAX-phase Ti3SiC2, various approaches based on heat treatment and consolidation of powder mixtures 3Ti/1.8SiC/0.8C and 2Ti/1.2SiC/1.8TiC have been considered. The first approach consists in powder heat treatment by vacuum sintering at 1400°C for 1 h and spark plasma sintering at 1350°C and a pressure of 50 MPa. The second approach consists in two-stage heat treatment, including additional consolidation by spark plasma sintering of vacuum-sintered composites. For each of the approaches, the effect of temperature and holding time during spark plasma sintering on the phase composition, density, and porosity of the obtained composites has been determined. It has been found that the consolidation of Ti3SiC2–TiC–Ti5Si3–TiSi2 and Ti3SiC2–TiC composites obtained by vacuum sintering and spark plasma sintering with the addition of 5 wt % of SiC leads to the formation of high-density Ti3SiC2–TiC–TiSi2 composites with an open porosity index of up to 0.3% and MAX-phase content from 9 to 33 vol % depending on the sintering temperature (1300–1400°C). It has been shown that the microstructure of the composite surfaces synthesized by spark plasma is represented by agglomerates of MAX-phase grains of Ti3SiC2, TiC, and inclusions of secondary phases (SiC and Ti5Si3 depending on the sintered composition).